diff options
Diffstat (limited to 'src/test/ui/borrowck/borrowck-overloaded-index-and-overloaded-deref.rs')
-rw-r--r-- | src/test/ui/borrowck/borrowck-overloaded-index-and-overloaded-deref.rs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/test/ui/borrowck/borrowck-overloaded-index-and-overloaded-deref.rs b/src/test/ui/borrowck/borrowck-overloaded-index-and-overloaded-deref.rs new file mode 100644 index 000000000..0e3e01a93 --- /dev/null +++ b/src/test/ui/borrowck/borrowck-overloaded-index-and-overloaded-deref.rs @@ -0,0 +1,36 @@ +// Check that we properly record borrows when we are doing an +// overloaded, autoderef of a value obtained via an overloaded index +// operator. The accounting of the all the implicit things going on +// here is rather subtle. Issue #20232. + +use std::ops::{Deref, Index}; + +struct MyVec<T> { x: T } + +impl<T> Index<usize> for MyVec<T> { + type Output = T; + fn index(&self, _: usize) -> &T { + &self.x + } +} + +struct MyPtr<T> { x: T } + +impl<T> Deref for MyPtr<T> { + type Target = T; + fn deref(&self) -> &T { + &self.x + } +} + +struct Foo { f: usize } + +fn main() { + let mut v = MyVec { x: MyPtr { x: Foo { f: 22 } } }; + let i = &v[0].f; + v = MyVec { x: MyPtr { x: Foo { f: 23 } } }; + //~^ ERROR cannot assign to `v` because it is borrowed + read(*i); +} + +fn read(_: usize) { } |